It depends on the size of your room and light set up.
Also the strain is important cuz if you have a strain that bushes out than that will take up more grow room and light space.
Also the size of your pots is important. 6 inch pots generally produce single cola plants 8 ich two colas ect...
I'm in a situation right now. I figured my 36 x 24 area could hold 24 6 inch pots. Well it can but not 24 full size plants. 12 ideally. This is the kind of thing you need to learn the hard way. I'm 12/12 from seed on most of mine. just started to veg the last batch for a few weeks. So the plants are smaller 12- 24 inches when complete.(aprox 1 oz per plant estimate)
I have 3 small flowering (6 weeks @ 12/12)MP5K and Speed Queen)
7 Northern light females1 foot tall and slightly bushy 2 weeks flowering
8 seedlings 1 week from showing sex.
That's 18 pots. Now in 3 weeks the oldest 3 will be harvested and the 8 ready to show sex will and the males will be gone. 50% male/female ratio that's 7 pots removed.
Problem I have is I have 7 seedlings in veg and they will be ready for 12/12 in two weeks or so.
I'm back to a full house and will suffer light blockage on alot of lower braches and buds.
So I went too many. looking for somebody to take a few seedlings just in case.
From this point I'll be cloning and 12 plants @ a time is the magic number.4 rows of 3
Hope that helps.